How severe is CVE-2026-39873?

CVE-2026-39873 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-39873 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-39873?

CVE-2026-39873 affects Apple Macos. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-39873?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-39873 published?

CVE-2026-39873 was published on 2026-07-27 and last updated on 2026-07-28.

CVE-2026-39873

CVE-2026-39873 is a critical-severity vulnerability in Apple Macos with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-119.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 0% (26th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-119
Affected product: Apple Macos
Published: 2026-07-27
Last modified: 2026-07-28

Description

The issue was addressed with improved memory handling. This issue is fixed in macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, macOS Tahoe 26.6. Connecting to a malicious SMB server may lead to unexpected system termination.

Frequently asked questions

What is CVE-2026-39873?: The issue was addressed with improved memory handling. This issue is fixed in macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, macOS Tahoe 26.6. Connecting to a malicious SMB server may lead to unexpected system termination.
How severe is CVE-2026-39873?: CVE-2026-39873 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-39873 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-39873?: CVE-2026-39873 affects Apple Macos. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-39873?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-39873 published?: CVE-2026-39873 was published on 2026-07-27 and last updated on 2026-07-28.

References

Affected products (1)

cpe:2.3:o:apple:macos:*:*:*:*:*:*:*:*

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